The Sharks signed the 23-year-old Swede to a four-year, $14 million US offer sheet on Friday, forcing the Stanley Cup champs to make another tough monetary decision. If Chicago had decided not to match the offer, the club would have received draft picks from the Sharks as compensation.

"Niklas was a big part of our success last year and he's a part of our core that's going to be together for a long time," said Blackhawks general manager Stan Bowman. "I'm happy for him. He's a quiet leader amongst our defensive group. I think he gets overshadowed because we've got other superstars there, but he was really effective for us all year long."

In his first full NHL season, Hjalmarsson totaled two goals and 15 assists in 77 regular-season games. He added a goal and eight points in 22 playoff games, helping the Blackhawks win the franchise's first Cup since 1961.

Hjalmarsson previously played parts of two seasons with Chicago and has compiled three goals and 18 helpers over 111 career regular-season games.

The Blackhawks have traded players such as playoff hero Dustin Byfuglien and Kris Versteeg to get under the salary cap.